This invention relates generally to fluid displacement apparatus such as hydraulic pumps, rams or the like, and to methods of displacing fluid under pressure to perform work. More particularly, this invention deals with an improved method and means for displacing fluid through the medium of a flexible cable or the like.
Various machines or apparatus for obtaining a mechanical advantage through the medium of hydraulic pressure have been employed for many years to perform useful work. One of the better known hydraulic tools is the common hydraulic jack which utilizes the movement of a small area piston to displace a relatively larger area piston.
The prime disadvantage of this type of hydraulic jack is that the small piston must move many times the distance moved by the large piston. The distance moved by the pistons is proportional to their cross sectional areas. If a relatively large working stroke is required by the larger of the pistons, then this technique becomes impractical because of the tremendous length of the stroke required by the small piston.